1. Field of the Invention
The present invention relates to a tool cutting apparatus including a cutting tool for cutting a workpiece and also to a tool cutting method for a workpiece.
2. Description of the Related Art
There are various techniques for realizing a reduction in size and weight of a semiconductor device. For example, a mounting technique called flip chip bonding has been put to practical use. This mounting technique is such that a plurality of metal projections called bumps each having a height of about 10 to 100 μm are formed on the front side of each device formed on a semiconductor wafer and these bumps are directly bonded to electrodes formed on a wiring board. The bumps on the device surface of the semiconductor wafer are formed by plating or a stud bump method. Accordingly, the heights of the individual bumps are not uniform, so that it is difficult to uniformly bond all the bumps to the electrodes of the wiring board.
Further, as a technique for realizing high-density wiring, there is an integrated circuit mounting technique such that an anisotropic conductive film (ACF) is interposed between the bumps and the wiring board to be bonded. In this mounting technique, the heights of the bumps must be uniformed because the lack of the height of any bump causes faulty bonding. It is therefore desirable to cut the plural bumps formed on the front side of a semiconductor wafer so that the heights of all the bumps become a desired height. As a method of cutting the bumps to a desired height, there has been proposed a cutting method using a tool cutting apparatus as disclosed in Japanese Patent Laid-Open No. 2010-36300.
The tool cutting apparatus includes a tool wheel composed of a wheel base and a tool unit provided on the wheel base, wherein the tool unit includes a cutting tip formed of diamond. In cutting a workpiece by using the tool cutting apparatus, the tool wheel is mounted on a spindle and rotated by rotating the spindle, and the cutting tip of the tool unit is brought into abutment against the workpiece, thereby making the cutting tip slide on the tool wheel and the workpiece